Just recently went on a highway trip with my 12' rcsb 4.7L. I recently bought it so I was pretty interested on what mpg I could get compared to the sticker numbers (14/20). After driving averaging about 65 mph, I got 22.2 mpg and was hand calculated. Im pretty happy with it compared to the sticker numbers thanks to a few changes such as a k & n air filter and maxing out my tire pressure. These numbers were from 20% city/ 80% highway!
Here is a vid I did to help those who are in need of some tips. I hope to soon reach my goal of 25 mpg in the near future.